We asked a selection of current and ex-employees of U.S. banks in London for their perceptions of the character types best suited to the firms they work for or have recently left. We also asked senior headhunters for their perspectives on the different types of people found at different U.S. banks. Their answers - almost always provided off the record, and often contradictory, are given below.

The personality types at Goldman Sachs: Low-key drinkers of the Corporate Kool-Aid, with hidden depths of competitiveness

If you like collaboration and drinking the corporate Kool Aid, you'll love working for Goldman Sachs. The 'firm' has a reputation for demanding subjugation to the employer brand and dedication to client satisfaction.

"It's all about collaboration and teamwork at Goldman," says one ex-associate who spent six years working for the firm. "There are some big brash bankers there, but most are low key and are doing what they do because they think it's the right thing for clients."

Another ex-Goldman banker who's worked for other firms, says Goldman bankers are "quietly confident" - and with good reason. "The average at Goldman is higher than anywhere else. They understand problems better and can provide solutions that are smarter." People at Goldman don't need to draw attention to their wealth and achievements, he says - they tend to be understated.

Not everyone agrees with this sedate portrayal of Goldman-types, however. One fixed income headhunter who works with Goldmanites says they can be, "incredibly aggressive" and that at the junior end the bank 'churns staff' at a rapid rate. "If you go to Goldman you'll work out quite quickly whether it's for you," he says. "A lot of the senior guys at Goldman are home grown, but if you're a junior there it can be pretty intense, with long hours and high stress."

An ex-JPMorgan fixed income trader also contested the portrait of rivals at Goldman Sachs as quietly confident and collaborative. "They're very arrogant. If you go to a dinner party and there's a Goldman person there, you'll spot them a mile off. It attracts the kind of people who define themselves by their business card."

If you are arrogant, don't display it at your Goldman interview. It's one of the things the firm says it screens against.

The personality types at JPMorgan: 'Nice, fun guys', drinkers of the Corporate Kool-Aid, with a willingness to operate as a small cog in a big machine

If you like bureaucracy, you'll like JPMorgan. While Goldman Sachs employed 32,400 people across the firm at the last count, JPMorgan employs 245,000. Admittedly, only 52,000 of those are in JPMorgan's corporate and investment bank, with just a fraction of them in the actual investment bank, but JPMorgan like its businesses to operate synergistically. You will be one of many.

"You're a small cog at JPMorgan," says an ex-JPM trader. "Your job is to keep your hamster wheel turning." He added that JPMorgan people are generally 'nice' - "There's none of the intellectual superiority you get at Goldman Sachs."

An ex-JPMorgan M&A banker agrees that it's a pleasant place to work. "JPMorgan is a friendly place," says Ferdinand Petra, affiliate professor of finance at HEC and a former associate at JPM for four years. "There are a lot of smart and hard working people there who are nice to work with and good to have drinks with after work. JPM people work hard and play hard. They're very open minded," he adds. "People there are fun - my feeling is that Goldman is a bit more serious."

Another ex-JPM saleswoman says the bank's culture has changed since the financial crisis, however, and that JPM isn't as nice as it used to be. "It seemed to be that JPMorgan changed after 2008 - there was an attitude that it did well while other banks faltered because it was better than everyone else, while in fact it was just lucky. They've got very into the idea that they're the best bank in the world and that you should want to be a part of all that. - It's a bit of a cult thing, a bit like Goldman Sachs."

If you like good manners, you'll like Morgan Stanley. "There's something a bit uptight about your average Morgan Stanley employee," says one ex-MS vice president. "People there are a lot less brash than at other banks. You'll fit in if you're quite formal and low key and you like to dress conservatively."

There aren't many mavericks at Morgan Stanley, she adds. The bank has traditionally been known for its elite 'white shoe' culture, which it recruited a lot of wasps (white Anglo Saxon protestants). These days, however, it's heavily into diversity and political correctness. "Morgan Stanley is a very straight player, very American, very conscious of being seen to do the right thing by women's careers," the ex-VP says.

One M&A headhunter suggests Morgan Stanley bankers can be keen on themselves: "There's a bit more arrogance in Morgan Stanley people than in Goldman people in my experience," he says.

The personality types at Bank of America Merrill Lynch: Restless entrepreneurial chameleons who can operate in a bureaucratic structure

If you like the energy of an expanding business, but can tolerate working in a large U.S.-centric bureaucracy, you'll like Bank of America Merrill Lynch (BAML).

BAML has been through a lot of changes. Not only was there the emergency merger between Bank of America and Merrill Lynch in late 2008, but the combined bank has done a lot of hiring - especially from Goldman Sachs, which has proven one of its most fertile territories for recruitment. Because of this, headhunters say that in London at least, BAML is a bit of everything. People there are chameleons who are more open to change and more aware of the perils of hubris than employees at some rival U.S. firms.

At the same time, Bank of America is a giant place. At last count, it employed 233,200 people - many of them in retail banking and operational roles. Bank of America Merrill Lynch is therefore a small unit within a big bureaucracy. Unlike JPMorgan's investment bank, which is similarly situated but can ride on the cachet of its success during the financial crisis, BAML had the wind knocked out of it by Merrill's near collapse. This makes it less complacent, say headhunters. "The people at BAML are entrepreneurial," says one London debt capital markets headhunter. "Because they've been building out there are less people with very long tenure than at some other banks. They're quite commercial and aggressive - you can't just wait for the franchise to do the work for you."

The personality types at Citi: Nice, down-to-earth, franchise men and women

Finally, if you're a pleasant person who wants to work in banking but is happy to work for a very big organisation that pulls in clients by virtue of its sheer enormity, Citi may be for you.

"Citi is a really friendly place," says one ex-Citi saleswoman who quit for JPMorgan (in search of more money). "The people there were much nicer and more down to earth than at other banks."

One headhunter claims that people at Citi enjoy a slower and more connected pace of life than at rival U.S, banks in London. "It's quite a franchise-based business. They have a lot of long-serving old timers and there's a big emphasis on all areas of the business working together," he claims.